Explanation
Cannot help but; cannot resist doing; an irresistible urge.
Formation
Verb-ない form (drop ない) + ずにはいられない
Detailed explanation
The ～ずにはいられない grammar point expresses that one cannot resist or help doing something. In other words, there is a strong urge that one cannot suppress. It's formed from the negative stem of a verb plus ずにはいられない. (Note: する → せずにはいられない.)
Examples
Kono kyoku o kiku to, utawazu ni wa irarenai.
When I hear this song, I can’t help but sing.
Kanojo ga naite iru no o miru to, nagusamezu ni wa irarenai.
When I see her crying, I can’t resist comforting her.
Kono shousetsu wa omoshiroi no de, yomazu ni wa irarenai.
This novel is so interesting that I can’t help but read it.
Kare wa oishii ryouri o mae ni suru to, tabezu ni wa irarenai.
When he’s faced with delicious food, he can’t help but eat it.
Practice
Grammar content sourced from hanabira.org.